I have two mallards. One is a disabled drake and the other is a normal female. They are both indoor, outdoor ducks. During the day Delilah is free to roam our backyard and forage as she pleases but at night she sleeps inside with Ferdinand in a spare bedroom with food and water. We have not found any eggs in our backyard and we are worried about why she wouldn't be producing eggs by 8 months. Any tips?